For the dissipation of heat produced during operation, electric machines, such as motors and/or generators have cooling systems filled with a coolant, wherein it is possible to achieve a dissipation of heat by circulation of the coolant, for example.
Electric machines of this kind are known from the prior art.
Thus, WO 2014/011 511 A2 describes an electric machine that is cooled by a conductive cooling fluid, wherein the cooling fluid flows through a cooling channel arrangement that is arranged in direct contact with stator windings of the electric machine. In this case, the component having the cooling channels is arranged between the stator windings and the associated stator yoke. A gap or an insulating layer is situated between the component having the cooling channels and the stator winding, in order to prevent the occurrence of eddy currents.
EP 2 852 030 A1 describes a cooling device for an electric machine with a stator that comprises at least one stator winding and at least one laminated stator core with at least one stator winding head, wherein the cooling device, which comprises a plurality of channels through which a coolant can flow, are connected at a first terminal section to a pressure reservoir and at their second terminal section end at a baffle cooling plate of the stator winding head. In this case, it needs to be ensured that, in the case of a conductive coolant, no short circuit is created between electrically conducting components of the electric machine.
Furthermore, it is generally known that a shaft grounding that is required under certain circumstances for grounding the shaft of the electric machine can be realized by an electrical contact at the shaft by way of, for example, a sliding contact. Such a shaft grounding serves, for example, for electromagnetic compatibility of the electric machine and for reduction of bearing currents, which can lead to an increased wear of the shaft bearings of the electric machine.